Cool Math
http://www.coolmath4kids.com

Clever Games for Clever People
http://www.cs.uidaho.edu/~casey931/conway/games.html

Design a Roller Coaster
http://www.esc2.net/TIELevel2/projects/roller/

Distance, Speed, and Time Relationships
http://standards.nctm.org/document/eexamples/chap5/5.2index.htm

Math Baseball
http://www.funbrain.com/math/

Math Bingo
http://www.aplusmath.com/games/index.html

Math Facts Game
http://home.indy.rr.com/lrobinson/mathfacts/mathfacts.html

Mega Math
http://www.c3.lanl.gov/mega-math/

Pattern Blocks and Fractions
http://math.rice.edu/~lanius/Patterns/

The Factor Game
http://illuminations.nctm.org/imath/6-8/FactorGame/factor1.html

Word Problems
http://www.stfx.ca/special/mathproblems/grade6.html

Enchanted Learning
http://www.enchantedlearning.com/

Fun Brain
http://www.funbrain.com/

National Geographic - Kids
http://kids.nationalgeographic.com/

PBS
http://www.pbs.org/

Scholastic
http://www.scholastic.com/

Seussville - Cat in the Hat 50th Birthday
http://www.seussville.com/main.php?section=home&isbn=&catalogID=&eventID

Starfall
http://www.starfall.com

Weekly Reader Online
http://www.weeklyreader.com/

Atlapedia Online
http://www.atlapedia.com/

CIA World Factbook
http://www.odci.gov/cia/publications/factbook/index.html

MSN Encarta Encyclopedia
http://encarta.msn.com/artcenter_/browse.html
 

FOSS Web Insects
http://www.fossweb.com/modulesK-2/Insects/index.html

Weather
http://www.weatherwizkids.com/